Basing your spell choices on gearing may sound good on paper, but it doesn't pan out so well in theory. Ultimately, doing so forces you into making more rigid choices. By prioritizing throughput stats over Spirit, you're implicitly favoring your more efficient heals. However, you'll find that you often have to cast your inefficient heals on progression, and I'd rather a healer have the buffer from the extra Spirit to do so.
Also, assuming a decent level of competency, where exactly is the error in adjusting your Spirit levels based on your experiences with healing the encounter? There have been many times this tier where I've felt that I had too much Spirit and vice versa, and optimizing my gear based on my experience with the content seems to be the most optimal solution. This is especially since there really isn't an optimal healing rotation, at least not one that's completely set in stone.
First, some assumptions.
- I'm talking right now about periods of sustained high damage (something like, say, Garalon when there's a lot of Pheromone stacks out).
- The raid is relatively stacked.
- You'll always cast your CD heal first. A raid healing Holy Priest is going to cast something along the lines of Divine Hymn, Holy Word: Sanctuary, level 90 talent, then Circle of Healing and Prayer of Mending, and then fill the rest of the time they have available between those cooldowns
with Prayer of Healing.
In this situation, there is a cap on the ratio of CD spells to efficient spells (Prayer of Healing, in this case). If you assume you always cast your CD spells on CD, there is only a finite number of POH casts you can fit in between them, and thus, there's a cap on how valuable Spirit will be in this situation.
- One player is low on health and is in danger of dying to incoming damage in the next 3 seconds. (I'm thinking of a player who was stacked up for Caw and got smacked down to about 10%, and Quills is coming up in 3 seconds).
- You will cast your highest HPS single target spell, regardless of cost. (I'd say even a Serenity Chakra Holy Priest would avoid casting HW:Serenity although I'm not 100% sure if FH is actually higher HPS than HW:Serenity. I'd assume a Disc Priest would cast a PW:S, Monk would probably cast Surging Mist).
Look at your average healer spreadsheet, and you'll see this ratio often calculated: HPM, healing divided by mana. When you assume that Spirit just gives you a chunk of mana, doled out in small increments over the course of the fight, this ratio can be looked at in another way: Healing divided by Spirit. So another way of saying a spell has high HPM is saying that spell benefits very well from Spirit. Thus, POH and Greater Heal are spells that like Spirit. However, Flash Heal doesn't like Spirit *at all*. In fact, the more you have to use Flash Heal over, say Greater Heal, the less benefit you are actually getting from your Spirit!
All that last point really emphasizes is that any point where you have to cast your Flash Heal equivalent to save a life is probably a point where your target has made a mistake, unless it was a tank, and even then it was probably a mistake.
Would it still be beneficial to stack Spirit if you knew that you were going into a fight that would force you to cast Flash Heal equivalents over and over? I don't know, but the relatively low benefit from Spirit that Flash Heal equivalents get leads me to think no. Finally, gearing like this doesn't create a rigid playstyle.
You, the player, still have to decide what situation you are in. Are you in Situation #1 or Situation #2? Or perhaps a situation where you need sustained, efficient healing on a single target (sort of like Splash on Lei Shi, at least at the start). Perhaps you're in a situation where the damage is light, no one's in danger, and there's no reason to blow an excessive amount of resources healing things up when background healing from CDs throughout the raid (COH, Wild Growth, Healing Rain, and the like) will do the job just fine? No theorycrafter can tell you which situation you are in. Theorycrafting can only tell you that once you've chosen the situation you are in, which spells are best suited for the job and which stat is the best to have on your gear for those situations.
I agree with that, on the first page I posted the gist of my mathematical model to deal exactly with that for a pure raid healing perspective.
You left out the CD math for Shamans. I'd actually be interested in seeing that.